By Debbie Emery - Breaking Celebrity News Reporter

What happens in Vegas doesn't always stay in Vegas, especially when The Real Housewives of Beverly Hills hit Sin City!

The cast was there last weekend to shoot a special episode of the show, and Breaking Celebrity News has exclusive behind-the-scenes details on the drama that went down.

"Lisa Vanderpump had a huge break down on the plane ride home," an insider exclusively revealed. "She and Kyle Richards have been working hard to repair their relationship after last season and things came to a head."

As Breaking Celebrity News previously reported, the British reality matriarch recently told Richards that she had better get in line, and either be with her or against her.

After playing hardball just a few months ago, Vanderpump showed her sensitive side coming home from the Vegas trip, much to the surprise of all her costars.

"Lisa was talking about how hurt she had been by Kyle turning on her at the end of the season and she burst into tears," the show source told Breaking Celebrity News.

"None of the women had ever seen Lisa cry like that and they were completely in shock.  Kyle felt awful and was doing everything she could to comfort her."

Luckily, the midair meltdown had a positive side affect by reuniting the old allies. "Their friendship is in a much better place but it hasn't totally healed yet," said their pal.

Meanwhile, newcomer